Surgical treatment of femoroacetabular impingement following slipped capital femoral epiphysis: A systematic review

Hip Impingement of severe SCFE patients after in situ pinning causes decreased flexion and forced external rotation in flexion on 3D-CT

Introduction

In situ pinning is an accepted treatment for stable slipped capital femoral epiphysis. However, residual deformity of severe slipped capital femoral epiphysis can cause femoroacetabular impingement and forced external rotation.

Purpose/questions

The aim of this study was to evaluate the (1) hip external rotation and internal rotation in flexion, (2) hip impingement location, and (3) impingement frequency in early flexion in severe slipped capital femoral epiphysis patients after in situ pinning using three-dimensional computed tomography.

Patients and methods

A retrospective Institutional Review Board-approved study evaluating 22 patients (26 hips) with severe slipped capital femoral epiphysis (slip angle > 60°) using postoperative three-dimensional computed tomography after in situ pinning was performed. Mean age at slipped capital femoral epiphysis diagnosis was 13 ± 2 years (58% male, four patients bilateral, 23% unstable, 85% chronic). Patients were compared to contralateral asymptomatic hips (15 hips) with unilateral slipped capital femoral epiphysis (control group). Pelvic three-dimensional computed tomography after in situ pinning was used to generate three-dimensional models. Specific software was used to determine range of motion and impingement location (equidistant method). And 22 hips (85%) underwent subsequent surgery.

Results

(1) Severe slipped capital femoral epiphysis patients had significantly (p < 0.001) decreased hip flexion (43 ± 40°) and internal rotation in 90° of flexion (-16 ± 21°, IRF-90°) compared to control group (122 ± 9° and 36 ± 11°). (2) Femoral impingement in maximal flexion was located anterior to anterior-superior (27% on 3 o'clock and 27% on 1 o'clock) of severe slipped capital femoral epiphysis patients and located anterior to anterior-inferior (38% on 3 o'clock and 35% on 4 o'clock) in IRF-90°. (3) However, 21 hips (81%) had flexion < 90° and 22 hips (85%) had < 10° of IRF-90° due to hip impingement and 21 hips (81%) had forced external rotation in 90° of flexion (< 0° of IRF-90°).

Conclusion

After in situ pinning, patient-specific three-dimensional models showed restricted flexion and IRF-90° and forced external rotation in 90° of flexion due to early hip impingement and residual deformity in most of the severe slipped capital femoral epiphysis patients. This could help to plan subsequent hip preservation surgery, such as hip arthroscopy or femoral (derotation) osteotomy.

Assessment of femoral retroversion on preoperative hip magnetic resonance imaging in patients with slipped capital femoral epiphysis: Theoretical implications for hip impingement risk estimation

Purpose

Slipped capital femoral epiphysis is a common pediatric hip disease and was associated with femoral retroversion, but femoral version was rarely measured. Therefore, mean femoral version, mean femoral neck version, and prevalence of femoral retroversion were analyzed for slipped capital femoral epiphysis patients.

Methods

A retrospective observational study evaluating preoperative hip magnetic resonance imaging of 27 patients (49 hips) was performed. Twenty-seven untreated slipped capital femoral epiphysis patients (28 slipped capital femoral epiphysis hips and 21 contralateral hips, age 10-16 years) were evaluated (79% stable slipped capital femoral epiphysis, 22 patients; 43% severe slipped capital femoral epiphysis, 12 patients). Femoral version was measured using Murphy method on magnetic resonance imaging (January 2014-December 2021, rapid bilateral 3-dimensional T1 water-only Dixon-based images of pelvis and knee). All slipped capital femoral epiphysis patients underwent surgery after magnetic resonance imaging.

Results

Mean femoral version of slipped capital femoral epiphysis patients (-1° ± 15°) was significantly (p < 0.001) lower compared to contralateral side (15° ± 14°). Femoral version of slipped capital femoral epiphysis patients had significantly (p < 0.001) wider range from -42° to 35° (range 77°) compared to contralateral side (-5° to 44°, range 49°). Mean femoral neck version of slipped capital femoral epiphysis patients (6° ± 15°) was lower compared to contralateral side (11° ± 12°). Fifteen slipped capital femoral epiphysis patients (54%) had absolute femoral retroversion (femoral version < 0°). Six of the 12 hips (50%) with severe slips and 4 of the 8 hips (50%) with mild slips had absolute femoral retroversion (femoral version < 0°). Ten slipped capital femoral epiphysis patients (40%) had absolute femoral neck retroversion (femoral neck version < 0°).

Conclusion

Although slipped capital femoral epiphysis patients showed asymmetrically lower femoral version compared to contralateral side, there was a wide range of femoral version, underlining the importance of patient-specific femoral version analysis on preoperative magnetic resonance imaging. Absolute femoral retroversion was prevalent in half of slipped capital femoral epiphysis patients, in half of severe slipped capital femoral epiphysis patients, and in half of mild slipped capital femoral epiphysis patients. This has implications for anterior hip impingement and for surgical treatment with in situ pinning or femoral osteotomy (e.g. proximal femoral derotation osteotomy) or other hip preservation surgery.

Limited Hip Flexion and Internal Rotation Resulting From Early Hip Impingement Conflict on Anterior Metaphysis of Patients With Untreated Severe SCFE Using 3D Modelling

INTRODUCTION

Slipped capital femoral epiphysis (SCFE) is the most common hip disorder in adolescent patients that can result in complex 3 dimensional (3D)-deformity and hip preservation surgery (eg, in situ pinning or proximal femoral osteotomy) is often performed. But there is little information about location of impingement.Purpose/Questions: The purpose of this study was to evaluate (1) impingement-free hip flexion and internal rotation (IR), (2) frequency of impingement in early flexion (30 to 60 degrees), and (3) location of acetabular and femoral impingement in IR in 90 degrees of flexion (IRF-90 degrees) and in maximal flexion for patients with untreated severe SCFE using preoperative 3D-computed tomography (CT) for impingement simulation.

METHODS

A retrospective study involving 3D-CT scans of 18 patients (21 hips) with untreated severe SCFE (slip angle>60 degrees) was performed. Preoperative CT scans were used for bone segmentation of preoperative patient-specific 3D models. Three patients (15%) had bilateral SCFE. Mean age was 13±2 (10 to 16) years and 67% were male patients (86% unstable slip, 81% chronic slip). The contralateral hips of 15 patients with unilateral SCFE were evaluated (control group). Validated software was used for 3D impingement simulation (equidistant method).

RESULTS

(1) Impingement-free flexion (46±32 degrees) and IRF-90 degrees (-17±18 degrees) were significantly ( P <0.001) decreased in untreated severe SCFE patients compared with contralateral side (122±9 and 36±11 degrees).(2) Frequency of impingement was significantly ( P <0.001) higher in 30 and 60 degrees flexion (48% and 71%) of patients with severe SCFE compared with control group (0%).(3) Acetabular impingement conflict was located anterior-superior (SCFE patients), mostly 12 o'clock (50%) in IRF-90 degrees (70% on 2 o'clock for maximal flexion). Femoral impingement was located on anterior-superior to anterior-inferior femoral metaphysis (between 2 and 6 o'clock, 40% on 3 o'clock and 40% on 5 o'clock) in IRF-90 degrees and on anterior metaphysis (40% on 3 o'clock) in maximal flexion and frequency was significantly ( P <0.001) different compared with control group.

CONCLUSION

Severe SCFE patients have limited hip flexion and IR due to early hip impingement using patient-specific preoperative 3D models. Because of the large variety of hip motion, individual evaluation is recommended to plan the osseous correction for severe SCFE patients.

LEVEL OF EVIDENCE

Level III.

Clinical and radiological outcomes following surgical hip dislocation for paediatric hip pathologies, a prospective cohort study

BACKGROUND

Surgical Hip Dislocation (SHD) is a powerful tool in the armamentarium of any surgeon treating conditions affecting the hips of children presenting with sequelae of a number of common conditions including Legg-CalvéPerthes disease (LCPD) and slipped capital femoral epiphysis (SCFE). Risks associated with the procedure are well described. We investigated to assess if SHD is associated with significant surgical risk and if it improved clinical outcomes for patients.

METHODS

We conducted a prospective cohort study. We reviewed 18 (11 males and 7 females; mean age 13.7 years (6-17) with symptomatic hip pathology, secondary to femoroacetabular impingement (FAI) between 2017 and 2021. All patients underwent a surgical hip dislocation approach and femoral head-neck osteochondroplasty, Head Split osteotomy or both. Clinical improvement was assessed using the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index. The minimum follow-up was 6 months (mean, 22 months; range, 6-42 months).

RESULTS

WOMAC scores improved at final follow-up from 10 to 3 for pain, 33 to 10 for function, and 4 to 2 for the stiffness subscales. All radiographic measures improved significantly of the postoperative X-rays. No patients developed osteonecrosis, implant failure, deep infection, or nonunion.

CONCLUSION

Surgical Hip Dislocation, in the short term, we found improvement in WOMAC scores and radiographic indices with a low complication rate.

The Effect of the Type of Screw Fixation Used in the Treatment of Slipped Capital Femoral Epiphysis

Background

Slipped capital femoral epiphysis (SCFE) remains among the most common hip disorders in the adolescent population. The management of SCFE remains controversial; however, the aim of fixation is to stabilize the physis and prevent further slippage. In situ fixation remains the gold standard; however, in the young population, it can lead to reduced femoral neck growth and complications such as leg length discrepancies. The ideal form of in situ fixation for mild to moderate SCFE would stabilize the slip and allow continued proximal femoral growth. This study aimed to determine if partially threaded screws allowed more neck growth than fully threaded screws.

Methods

A retrospective review of the radiographs of all patients undergoing in situ fixation for SCFE using partially threaded and fully threaded screws. Measurements included neck length, neck-to-screw ratio, neck shaft angle, neck width, and articular-trochanteric distance. Parameters were compared over a two-year period to determine whether there was any difference in proximal femoral growth between the two types of screws.

Results

Fully threaded screw neck length increased by 5 mm versus 5 mm for proximally threaded screws (P ≤ 0.001). No significant difference was observed between the two groups with respect to neck width, neck shaft angle, and articular-trochanteric distance.

Conclusions

No difference was observed in proximal femoral growth. Regardless of which type of fixation is used, neck length continues to increase by approximately 3 mm per year.

Outcomes in Pediatric Hip FAI Surgery: a Scoping Review

PURPOSE OF REVIEW

Femoracetabular impingement (FAI) is a common source of hip pain in children and adolescents. While nonoperative therapies and open surgical procedures can be effective, hip arthroscopy is a minimally invasive treatment option with substantial benefit. The purpose of this paper is to evaluate the current role of hip arthroscopy in treating FAI within the pediatric population. This article examines its efficacy through a review of hip arthroscopy outcomes in the contemporary orthopaedic literature.

RECENT FINDINGS

Morphologic changes in the acetabulum and proximal femur seen in FAI can be attributed to a multitude of etiologies-including idiopathic FAI, Legg-Calve-Perthes, and slipped capital femoral epiphysis. In general, arthroscopic treatment of FAI secondary to these conditions leads to statistically significant improvements in pain and patient-reported outcomes in the short and long term. In the pediatric athlete, repetitive stress on the hip perpetuates FAI and can drastically hinder performance. Hip arthroscopy allows for a high rate of return to sport with minimal morbidity in this population. Overall, pediatric hip arthroscopy is effective in treating FAI secondary to a wide variety of conditions. Despite its clinical benefits, patients and their families should be counseled regarding alternative treatments, potential complications, and return to play.

Risk factors for early symptomatic femoroacetabular impingement following in situ fixation of slipped capital femoral epiphysis

In situ fixation of slipped capital femoral epiphysis (SCFE) results in residual deformity that can cause femoroacetabular impingement (FAI). It is unknown what factors could help differentiate patients who are more likely to become symptomatic. We performed a retrospective review of 55 hips treated with in situ pinning for SCFE and subsequent secondary deformity correction procedure for symptomatic FAI and compared them to 39 asymptomatic hips with SCFE deformity using multivariable analysis. Case patients were slightly older than controls (12.6 vs 11.3 years, p = 0.0002) but had similar BMI. The mean epiphyseal-diaphyseal angle was 56° in cases versus 44° in controls (p = 0.0019). Cases were significantly more likely to have obligate external rotation with hip flexion, external foot progression, flexion <90°, antalgic limp, and Trendelenburg lurch. On radiographs, most cases had a head-neck offset ≤0 mm, a distinct metaphyseal corner prominence, acetabular retroversion, and an alpha angle ≥60°. Most controls also had head-neck offset ≤0 mm. Pre-pinning, older age (OR = 1.98 per year, p = 0.0016) and initial epiphyseal-diaphyseal angle (OR = 1.04 per degree, p = 0.018) significantly increased the odds of having symptomatic FAI. Post-pinning, external foot progression increased the odds of symptomatic FAI by 10.48 (p = 0.017), and an alpha angle ≥60° resulted in 11.4 times higher odds of symptomatic FAI (p = 0.011). The linear correlation between epiphyseal-diaphyseal and alpha angle was poor (r = 0.28). Older age and initial epiphyseal-diaphyseal pre-pinning mildly increased the odds of eventual symptomatic FAI. This information can help the surgeon to predict which patients may develop symptomatic FAI.

Surgical treatment of slipped capital femoral epiphysis (SCFE) by Dunn procedure modified by Ganz: a systematic review

BACKGROUND

Treatment of SCFE is still controversial, especially in moderate and severe forms. Dunn osteotomy performed with the Ganz approach became very popular in the last decade, although it is a complicated and challenging surgical procedure with a risk of AVN. The aim of our study was to analyze the current literature verifying the effectiveness of this surgical procedure, with specific attention to the incidence of AVN and other complications.

MAIN BODY

A systematic review on the subject was performed according to the PRISMA guidelines. A literature search was performed by searching all published articles about the topic in the databases. The articles were screened for the presence of the following inclusion criteria: patients affected by slipped capital femoral epiphysis (SCFE) surgically treated by Dunn osteotomy using the Ganz surgical approach. All the patients affected by pathologies other than SCFE, treated without surgery or with procedures not including a surgical hip dislocation were excluded. Based on inclusion and exclusion criteria, 23 studies were included in our systematic review. Selected articles were published from 2009 to 2021 and they included 636 overall hips. According to the selected articles, Dunn osteotomy modified by Ganz, performed by an experienced surgeon, allows for anatomical reduction of moderate or severe SCFE with a low incidence of AVN.

CONCLUSIONS

The few papers with long term follow-up, reported no progression of hip osteoarthritis, however, since the patients are adolescent at surgery, longer follow-up studies are needed to validate this statement. It is still debated if better results are obtained in stable or unstable SCFE. The indication of this procedure in mild SCFE remains controversial.

LEVEL OF EVIDENCE

3.

Outcomes After Arthroscopic Osteochondroplasty for Femoroacetabular Impingement Secondary to Slipped Capital Femoral Epiphysis: A Systematic Review

PURPOSE

To determine the efficacy of arthroscopic osteochondroplasty for patients with femoroacetabular impingement (FAI) secondary to slipped capital femoral epiphysis (SCFE).

METHODS

A systematic review was performed based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using Embase, PubMed (Medline), and Cochrane Library up to November 1, 2019. Data including patient demographics, slip severity according to Southwick, outcomes, and complications were retrieved from eligible studies that reported a minimum 3-month follow-up of arthroscopic osteochondroplasty for FAI secondary to SCFE. Methodological Index for Non-Randomized Studies (MINORS) criteria was used to assess quality of studies. Heterogeneity and quality were evaluated using P values and the I² statistic.

RESULTS

Six studies (90 hips) were analyzed. The range of MINORS scores was 8 to 11. Most studies were level of evidence 4 (n = 4, 66.7%), with more men than women (n = 5, 83.3%). The ranges of age, body mass index, and follow-up length after surgery were 10 to 42 years, 17.5 to 32.3 kg/m², and 3 to 56 months, respectively. The Modified Harris Hip Score (mHHS) was the most commonly used score to report on clinical outcomes (n = 2 studies, 28 hips) with a significant improvement following surgery. Three studies reported an improvement in internal rotation (IR) of the hip with a range of improvement of 17° to 32°, with low heterogeneity (I² = 0% and P = .531). Five studies reported a significant correction of the α angle, with range of improvement of 19.9° to 37.3°. The range of postoperative α angle was 32° to 67°, and 3 studies achieved appropriate postoperative α angle (40° to 50°), with low heterogeneity (I² = 8.4% and P = .336). The total number of complications was 8 (1 major complication) and there were 6 revisions, with low heterogeneity.

CONCLUSION

Arthroscopic osteochondroplasty for FAI secondary to SCFE provides good short- to medium-term outcomes and improves IR of the hip, with the ability to potentially correct the α angle with a low rate of complications and revision.

LEVEL OF EVIDENCE

IV, systematic review of level II to IV studies.

Does a History of Slipped Capital Femoral Epiphysis in Patients Undergoing Femoroacetabular Osteoplasty for Femoroacetabular Impingement Affect Outcomes Scores or Risk of Reoperation?

BACKGROUND

Femoroacetabular impingement (FAI) can occur after slipped capital femoral epiphysis (SCFE) regardless of slip severity and even after in situ pinning. These patients represent a rare and unique demographic that is largely unreported on. It is important to further characterize the clinical presentation of these patients, associated treatment modalities, and the efficacy of these treatment modalities.

QUESTIONS/PURPOSES

(1) How do patients with post-SCFE FAI typically present in terms of radiographic and surgical findings? (2) How do their hip-specific and general-health outcomes scores after mini-open femoroacetabular osteoplasty compare with those obtained in a matched group of patients with FAI caused by other etiologies? (3) How do those groups compare in terms of the proportion who undergo conversion to THA?

METHODS

Between 2013 and 2017, 20 patients had femoroacetabular osteoplasty for post-SCFE FAI. During that time, general indications for this procedure were symptomatic FAI demonstrated on radiographs and physical exam. Of those, none was lost to follow-up before a minimum of 2 years, leaving all 20 available for matching, and all 20 had suitable matches in our database for patients who underwent femoroacetabular osteoplasty for other diagnoses. Matching was performed by surgeon, patient age, patient gender, and BMI. The matching group was drawn from a large database of patients who had the same procedure during the same period. We matched in a 1:3 ratio to arrive at 60 randomly selected control patients in this retrospective, comparative study. Patient demographics, medical history, clinical presentation, radiographic parameters, and intraoperative findings were compared between the two groups. At a minimum of 2 years of follow-up, the latest clinical functional outcome scores (Hip Disability and Osteoarthritis Outcome Score Jr and SF-12) and proportions of conversion to THA were compared between the groups.

RESULTS

A greater percentage of patients with a history of SCFE than those without prior SCFE demonstrated full chondral lesions intraoperatively (90% [18 of 20] versus 32% [19 of 60], odds ratio 7 [95% confidence interval 1 to 178]; p < 0.01). A greater percentage of patients with a history of SCFE also demonstrated labral calcifications intraoperatively compared with those without prior SCFE (65% [13 of 20] versus 35% [21 of 60], OR 3 [95% CI 1 to 10]; p = 0.04). Radiographically, patients with SCFE had greater preoperative alpha angles than did patients without SCFE (94° ± 13° versus 72° ± 22°; p = 0.01) as well as lower lateral center-edge angles (25° ± 8° versus 31° ± 8°; p = 0.04). There was no difference in postoperative follow-up between patients with a history of SCFE and patients without a history of SCFE (4 ± 2 years versus 4 ± 2 years; p = 0.32). There was no difference in the mean postoperative outcome scores between patients with a history of SCFE and patients without (Hip Disability and Osteoarthritis Outcome Score Jr: 75 ± 28 points versus 74 ± 17 points; p = 0.95; SF-12 physical score: 40 ± 11 points versus 39 ± 8 points; p = 0.79). There was no difference with the numbers available in the percentage of patients who underwent conversion to THA (15% [3 of 20] versus 12% [7 of 60], OR 1.36 [95% CI 0 to 6]; p = 0.71).

CONCLUSION

Patients with FAI after SCFE present with a greater degree of labral and chondral disease than do patients without a history of SCFE. However, at short-term follow-up, the proportion of patients who underwent conversion to THA and patients' postoperative outcome scores did not differ in this small, comparative series between patients with and without SCFE. Further evaluation with long-term follow-up is needed, especially given the more severe chondral damage we observed in patients with SCFE at the time of surgery.

LEVEL OF EVIDENCE

Level III, therapeutic study.

How Common Is Femoral Retroversion and How Is it Affected by Different Measurement Methods in Unilateral Slipped Capital Femoral Epiphysis?

BACKGROUND

Although femoral retroversion has been linked to the onset of slipped capital femoral epiphysis (SCFE), and may result from a rotation of the femoral epiphysis around the epiphyseal tubercle leading to femoral retroversion, femoral version has rarely been described in patients with SCFE. Furthermore, the prevalence of actual femoral retroversion and the effect of different measurement methods on femoral version angles has yet to be studied in SCFE.

QUESTIONS/PURPOSES

(1) Do femoral version and the prevalence of femoral retroversion differ between hips with SCFE and the asymptomatic contralateral side? (2) How do the mean femoral version angles and the prevalence of femoral retroversion change depending on the measurement method used? (3) What is the interobserver reliability and intraobserver reproducibility of these measurement methods?

METHODS

For this retrospective, controlled, single-center study, we reviewed our institutional database for patients who were treated for unilateral SCFE and who had undergone a pelvic CT scan. During the period in question, the general indication for obtaining a CT scan was to define the surgical strategy based on the assessment of deformity severity in patients with newly diagnosed SCFE or with previous in situ fixation. After applying prespecified inclusion and exclusion criteria, we included 79 patients. The mean age was 15 ± 4 years, 48% (38 of 79) of the patients were male, and 56% (44 of 79) were obese (defined as a BMI > 95th percentile (mean BMI 34 ± 9 kg/m2). One radiology resident (6 years of experience) measured femoral version of the entire study group using five different methods. Femoral neck version was measured as the orientation of the femoral neck. Further measurement methods included the femoral head's center and differed regarding the level of landmarks for the proximal femoral reference axis. From proximal to distal, this included the most-proximal methods (Lee et al. and Reikerås et al.) and most-distal methods (Tomczak et al. and Murphy et al.). Most proximally (Lee et al. method), we used the most cephalic junction of the greater trochanter as the landmark and, most distally, we used the center base of the femoral neck superior to the lesser trochanter (Murphy et al.). The orientation of the distal femoral condyles served as the distal reference axis for all five measurement methods. All five methods were compared side-by-side (involved versus uninvolved hip), and comparisons among all five methods were performed using paired t-tests. The prevalence of femoral retroversion (< 0°) was compared using a chi-square test. A subset of patients was measured twice by the first observer and by a second orthopaedic resident (2 years of experience) to assess intraobserver reproducibility and interobserver reliability; for this assessment, we used intraclass correlation coefficients.

RESULTS

The mean femoral neck version was lower in hips with SCFE than in the contralateral side (-2° ± 13° versus 7° ± 11°; p < 0.001). This yielded a mean side-by side difference of -8° ± 11° (95% CI -11° to -6°; p < 0.001) and a higher prevalence of femoral retroversion in hips with SCFE (58% [95% CI 47% to 69%]; p < 0.001) than on the contralateral side (29% [95% CI 19% to 39%]). These differences between hips with SCFE and the contralateral side were higher and ranged from -17° ± 11° (95% CI -20° to -15°; p < 0.001) based on the method of Tomczak et al. to -22° ± 13° (95% CI -25° to -19°; p < 0.001) according to the method of Murphy et al. The mean overall femoral version angles increased for hips with SCFE using more-distal landmarks compared with more-proximal landmarks. The prevalence of femoral retroversion was higher in hips with SCFE for the proximal methods of Lee et al. and Reikerås et al. (91% [95% CI 85% to 97%] and 84% [95% CI 76% to 92%], respectively) than for the distal measurement methods of Tomczak et al. and Murphy et al. (47% [95% CI 36% to 58%] and 60% [95% CI 49% to 71%], respectively [all p < 0.001]). We detected mean differences ranging from -19° to 4° (all p < 0.005) for 8 of 10 pairwise comparisons in hips with SCFE. Among these, the greatest differences were between the most-proximal methods and the more-distal methods, with a mean difference of -19° ± 7° (95% CI -21° to -18°; p < 0.001), comparing the methods of Lee et al. and Tomczak et al. In hips with SCFE, we found excellent agreement (intraclass correlation coefficient [ICC] > 0.80) for intraobserver reproducibility (reader 1, ICC 0.93 to 0.96) and interobserver reliability (ICC 0.95 to 0.98) for all five measurement methods. Analogously, we found excellent agreement (ICC > 0.80) for intraobserver reproducibility (reader 1, range 0.91 to 0.96) and interobserver reliability (range 0.89 to 0.98) for all five measurement methods in healthy contralateral hips.

CONCLUSION

We showed that femoral neck version is asymmetrically decreased in unilateral SCFE, and that differences increase when including the femoral head's center. Thus, to assess the full extent of an SCFE deformity, femoral version measurements should consider the position of the displaced epiphysis. The prevalence of femoral retroversion was high in patients with SCFE and increased when using proximal anatomic landmarks. Since the range of femoral version angles was wide, femoral version cannot be predicted in a given hip and must be assessed individually. Based on these findings, we believe it is worthwhile to add evaluation of femoral version to the diagnostic workup of children with SCFE. Doing so may better inform surgeons as they contemplate when to use isolated offset correction or to perform an additional femoral osteotomy for SCFE correction based on the severity of the slip and the rotational deformity. To facilitate communication among physicians and for the design of future studies, we recommend consistently reporting the applied measurement technique.

LEVEL OF EVIDENCE

Level III, prognostic study.

Surgical treatment of symptomatic post-slipped capital femoral epiphysis deformity: a comparative study between hip arthroscopy and surgical hip dislocation with or without intertrochanteric osteotomy

PURPOSE

Our primary research question was to investigate the severity of deformity and articular damage as well as outcomes in patients undergoing hip arthroscopy compared with open surgery for the treatment of symptomatic slipped capital femoral epiphysis (SCFE) deformity.

METHODS

Retrospective review of surgical treatment of symptomatic SCFE deformity with a minimum one-year follow-up. Patients were divided into three groups: the arthroscopic group, surgical hip dislocation(SHD) group and SHD with femoral osteotomy (SHD+ITO) group. Deformity severity was quantified. Hip outcome was assessed by the modified Merle d'Aubigné Postel (MDP) scores.

RESULTS

There were more severe slips treated by SHD and SHD+ITO. There was more severe deformity in the SHD+ITO group than the arthroscopy group (p < 0.001). There were more full thickness acetabular cartilage defects in the SHD and the SHD+ITO groups (> 40%) compared with the arthroscopy group (11%; p = 0.03). The SHD+ITO and SHD group had lower MDP scores compared with the arthroscopy group both before and after surgery but no difference was detected in the amount of improvement from surgery across groups (p > 0.05). Moderate and severe SCFEs had worse preoperative scores but improvement was not different compared with mild SCFEs (p > 0.05).

CONCLUSION

Patients undergoing open treatment had more severe SCFE deformity with more extensive articular damage at reconstructive surgery compared with patients undergoing arthroscopy. All groups with SCFE deformity had improved pain and hip function postoperatively.

LEVEL OF EVIDENCE

III.

The Outside-In Technique for Slipped Capital Femoral Epiphysis: A Safe and Reproducible Approach in Hip Arthroscopy

Femoroacetabular impingement syndrome caused by slipped capital femoral epiphysis (SCFE) can be successfully treated arthroscopically and with the minimally invasive, outside-in surgical technique. The advantages of the technique are that the residual cam-type deformity caused by the slippage can be corrected and reconstructed reliably and reproducibly before distracting the hip joint; and radiation with fluoroscopy is used for only definitive reduction and reconstruction, which is obtained with cannulated screws. In addition, this safe technique allows distraction of the hip after screw placement, without affecting the reconstruction, to address labral tears and chondrolabral delaminations caused by the impingement.

Treatment for Post-Slipped Capital Femoral Epiphysis Deformity

In situ pinning of slipped capital femoral epiphysis (SCFE) is a safe and effective treatment modality, but often results in residual deformity leading to femoroacetabular impingement, which may limit patient activities and predispose to early onset arthritis. Enhanced understanding of the implications of femoroacetabular impingement and new surgical techniques have prompted interest in treating post-slipped capital femoral epiphysis deformity to both improve current symptoms and delay or prevent hip arthrosis.

Evolving Understanding of and Treatment Approaches to Slipped Capital Femoral Epiphysis

PURPOSE OF REVIEW

To review slipped capital femoral epiphysis (SCFE), with a focus on new insights into its etiology and evolving methods of operative fixation.

RECENT FINDINGS

The epiphyseal tubercle and its size during adolescence are paramount to understanding the mechanism of SCFE. In chronic stable SCFE, the epiphysis rotates about the tubercle protecting the lateral epiphyseal vessels from disruption. In an acute unstable SCFE, the tubercle displaces, increasing the risk of osteonecrosis, also known as avascular necrosis (AVN). Intraoperative stability suggests that stable and unstable SCFE based on ambulation may be inaccurate. For stable SCFE, in situ pinning remains the most accepted treatment for mild slips with delayed symptomatic femoroacetabular impingement (FAI) management. Treatment of moderate to severe stable slips with realignment osteotomy leads to less femoral deformity and potentially better outcomes. However, it has a higher risk of complications, including AVN and chondrolysis. Our knowledge of the etiology for SCFE is evolving. The optimal technique for operative treatment of moderate to severe SCFE is controversial and varies by center. Well-controlled studies of these patients are needed to understand the best treatment for this difficult problem. Furthermore, increasing the awareness about SCFE is paramount to allow for early recognition and treatment of deformity at its early stages and avoiding severe SCFE deformity which has been associated with worse long-term outcomes.

[Mid-term effectiveness of surgical hip dislocation for femoroacetabular impingement]

Objective

To assess the mid-term effecitveness of femoroacetabular impingement (FAI) treated by surgical hip dislocation.

Methods

Between April 2014 and August 2015, 15 patients (16 hips) with FAI were enrolled in the study and treated with surgical hip dislocation. There were 12 males and 3 females with an average age of 36.6 years (range, 22-59 years). Among them, 14 cases involved in unilateral hip and 1 in bilateral hips. The mean disease duration was 28 months (range, 4-120 months). Preoperative visual analogue scale (VAS) score and Harris hip score were 7.9±1.0 and 44.1±9.3, respectively.

Results

All incisions healed by first intention. There was no main complication, such as vessel and nerve injuries and infection. All 15 patients were followed up 30-46 months (mean, 39.5 months). The VAS score was 2.5±1.6 at 3 months and 0.5±0.7 at last follow-up. The Harris score was 85.5±4.4 at 3 months and 95.6±3.9 at last follow-up. There were significant differences in two scores between pre- and post-operation and between 3 months and last follow-up ( P<0.05). The satisfaction rate of hip function was 93.8% (15/16) at last follow-up. X-ray examination showed that there was no sign of impingment at the femoral head and neck and acetabulum forming site of the affected hip joint, and no complication such as loosening of internal fixator, nonunion of osteotomy, avascular necrosis of femoral head, and heterotopic ossification occurred during follow-up.

Conclusion

The surgical hip dislocation is a safe and effective way to treat FAI in the mid-term follow-up, which can repair torn labrum and trim acetabulum and femoral neck.

Patients with severe slipped capital femoral epiphysis treated by the modified Dunn procedure have low rates of avascular necrosis, good outcomes, and little osteoarthritis at long-term follow-up

AIMS

The modified Dunn procedure has the potential to restore the anatomy in hips with severe slipped capital femoral epiphyses (SCFE). However, there is a risk of developing avascular necrosis of the femoral head (AVN). In this paper, we report on clinical outcome, radiological outcome, AVN rate and complications, and the cumulative survivorship at long-term follow-up in patients undergoing the modified Dunn procedure for severe SCFE.

PATIENTS AND METHODS

We performed a retrospective analysis involving 46 hips in 46 patients treated with a modified Dunn procedure for severe SCFE (slip angle > 60°) between 1999 and 2016. At nine-year-follow-up, 40 hips were available for clinical and radiological examination. Mean preoperative age was 13 years, and 14 hips (30%) presented with unstable slips. Mean preoperative slip angle was 64°. Kaplan-Meier survivorship was calculated.

RESULTS

At the latest follow-up, the mean Merle d'Aubigné and Postel score was 17 points (14 to 18), mean modified Harris Hip Score was 94 points (66 to 100), and mean Hip Disability and Osteoarthritis Outcome Score was 91 points (67 to 100). Postoperative slip angle was 7° (1° to 16°). One hip (2%) had progression of osteoarthritis (OA). Two hips (5%) developed AVN of the femoral head and required further surgery. Three other hips (7%) underwent implant revision due to screw breakage or change of wires. Cumulative survivorship was 86% at ten-year follow-up.

CONCLUSION

The modified Dunn procedure for severe SCFE resulted in a low rate of AVN, low risk of progression to OA, and high functional scores at long-term follow-up. The slip deformities were mainly corrected but secondary impingement deformities can develop in some hips and may require further surgical treatment. Cite this article: Bone Joint J 2019;101-B:403-414.

A Systematic Summary of Systematic Reviews on the Topic of Hip Arthroscopic Surgery

BACKGROUND

There is a rapidly growing body of literature on the topic of hip arthroscopic surgery.

PURPOSE

To provide an overall summary of systematic reviews published on the indications, complications, techniques, outcomes, and information related to hip arthroscopic surgery.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A systematic review of all hip arthroscopic surgery-related systematic reviews published between January 2000 and May 2018 was performed using PubMed, MEDLINE, and the Cochrane Library. Narrative reviews and non-English articles were excluded.

RESULTS

A total of 837 articles were found, of which 85 met the inclusion criteria. Included articles were summarized and divided into 6 major categories based on the subject of the review: femoroacetabular impingement (FAI), non-FAI indications, surgical technique, outcomes, complications, and miscellaneous.

CONCLUSION

A summary of systematic reviews on hip arthroscopic surgery can provide surgeons with a single source for the most current synopsis of the available literature. As the prevalence of orthopaedic surgeons performing hip arthroscopic surgery increases, updated evidence-based guidelines must likewise be advanced and understood to ensure optimal patient management.

Moderate and severe SCFE (Slipped Capital Femoral Epiphysis) arthroscopic osteoplasty vs open neck osteotomy-a retrospective analysis of results

AIM

We intend to compare the outcomes of arthroscopic osteoplasty with open neck osteotomy for correction of the hip impingement and improvement of hip function in children with moderate to severe healed Slipped Capital Femoral Epiphysis (SCFE). Our aim is to verify if arthroscopic osteoplasty could achieve the same outcome as open procedures.

PATIENTS AND METHODS

A retrospective analysis of the hospital hip database retrieved 187 cases of SCFE from 2006 to 2013. We found 12 patients underwent open neck osteotomy and deformity correction for moderate/ severe healed SCFE and ten underwent arthroscopic osteoplasty of the hip. We compared the outcomes between these groups.

RESULTS

In the arthroscopy cohort, the mean age at surgery was 15.8 years (range 13-19 years) and mean follow-up was 46.1 months (range 33-66 months). In the neck osteotomy group, the mean age at surgery was 14.6 years (11-20 years) and mean duration of follow-up was 49 months (36-60 months). The outcomes in arthroscopic osteoplasty group vs. open neck osteotomy were as follows: antero-posterior (AP) slip angle 9.2° (0.3°- 28.8°) vs 10.8° (1°-17.9°) (p = 0.0003), lateral slip angle 44.8° (36.5°-64.2°) vs 13.5° (1°-28.5°) (p = 0.00001), oblique plane deformity 47.1° (40.2°-53.5°) vs 16.7° (1°-28.6°) (p = 0.0003), alpha angle 61.88° (52.1°-123°) vs.34.6° (23.2°-45.6°) (p = 0.0003), anterior offset 0 mm (0 mm-2 mm) vs. 5 mm (2-13 mm) (p = 0.0003), modified Harris hip score (MHHS) 75.5 (58.75-96.8) vs. 90 (86.2-99) (p = 0.003), non-arthroplasty hip score (NAHS) 67.12 (18.75-100) vs. 92.1 (81.25-100) (p = 0.002), internal rotation 20° (0-20°) vs. 50° (30°-70°) (p = 0.0002), respectively.

CONCLUSION

Even though the radiographic correction lagged behind in the arthroscopic group, the functional outcomes achieved did convey the gain of function in this cohort. In carefully selected cases, arthroscopy could be a less invasive procedure which has desirable outcomes.

Slipped Capital Femoral Epiphysis: The European Perspective

Treatment of slipped capital femoral epiphysis remains a contentious and debated issue. The opinion for the correct method of treatment can differ not only between different continents and nations, but also between units and surgeons within individual units. We aim to review the European perspective on the treatment of slipped capital femoral epiphysis and consider the trends for treatment among the European orthopaedic surgical community.

The natural alpha angle of the femoral head-neck junction

Aims

Asphericity of the femoral head-neck junction is common in cam-type femoroacetabular impingement (FAI) and usually quantified using the alpha angle on radiographs or MRI. The aim of this study was to determine the natural alpha angle in a large cohort of patients by continuous circumferential analysis with CT.

Methods

CT scans of 1312 femurs of 656 patients were analyzed in this cross-sectional study. There were 362 men and 294 women. Their mean age was 61.2 years (18 to 93). All scans had been performed for reasons other than hip disease. Digital circumferential analysis allowed continuous determination of the alpha angle around the entire head-neck junction. All statistical tests were conducted two-sided; a p-value < 0.05 was considered statistically significant.

Results

The mean maximum alpha angle for the cohort was 59.0° (sd 9.4). The maximum was located anterosuperiorly at 01:36 on the clock face, with two additional maxima of asphericity at the posterior and inferior head-neck junction. The mean alpha angle was significantly larger in men (59.4°, sd 8.0) compared with women (53.5°, sd 7.4°; p = 0.0005), and in Caucasians (60.7°, sd 9.0°) compared with Africans (56.3°, sd 8.0; p = 0.007) and Asians (50.8°, sd 7.2; p = 0.0005). The alpha angle showed a weak positive correlation with age (p < 0.05). If measured at commonly used planes of the radially reconstructed CT or MRI, the alpha angle was largely underestimated; measurement at the 01:30 and 02:00 positions showed a mean underestimation of 4° and 6°, respectively.

Conclusion

This study provides important data on the normal alpha angle dependent on age, gender, and ethnic origin. The normal alpha angle in men is > 55°, and this should be borne in mind when making a diagnosis of cam-type morphology. Cite this article: Bone Joint J 2018;100-B:570–8.

Surgical treatment of femoroacetabular impingement after slipped capital femoral epiphysis

PURPOSE OF REVIEW

Femoroacetabular impingement (FAI) post slipped capital femoral epiphysis (SCFE) may lead to degenerative changes on the hip. We have reviewed the current procedures in the literature, aiming to correct the SCFE to prevent FAI and the ones that treat FAI post SCFE.

RECENT FINDINGS

The trends of managing moderated or severe SCFE is to correct the displacement by reduction and fixation with articular hematoma decompression in unstable hips and Dunn modified procedure even for unstable and stable situations. However, after FAI is settled, the options are osteochondroplasty by arthroscopy or surgical hip dislocation, associated or not to subtrocanteric osteotomy.

SUMMARY

Femoroacetabular impingement may occur in mild slips and certainly occur in cases of moderate and severe slips. The initial management depends on the severity and the stability of the slip.The modified Dunn procedure is a good option for the treatment of unstable SCFEs. Gentle closed reduction with capsulotomy (Parsch) may be considered whenever the surgeon is not comfortable with the modified Dunn procedure.Hips with open physis and stable moderate or severe SCFE, the modified Dunn procedure can be indicated. Cases with closed physis are managed with intertrochanteric osteotomy combined with osteoplasty.In the presence of symptomatic FAI secondary to SCFE, one should consider arthroscopic osteoplasty or surgical hip dislocation (with or without osteotomies) as treatment options.